Visual field testing is a conventional clinical method utilized in the diagnosis of eye diseases that cause degradation of vision sensitivity. One method utilized in the diagnosis of such diseases is the Standard Automated Perimeter (SAP) test, which tests brightness contrast sensitivity over a large visual field. There are many instruments for performing an SAP test routinely used in clinics including, for example, those produced by Carl Zeiss Meditec (Dublin, Calif.).
Typically, visual field testing utilizes functional field testing techniques. However, a functional field test technique is a functional test of vision degradation. Due to the human eye's complex multiplexing capability, the functional field test is not a sensitive measure of eye structure, which would be highly useful in the early diagnoses of such eye diseases before substantial degradation has occurred. Such structural tests include, for example, retinal image testing and optical coherence tomography (OCT).
Retinal image testing can be performed with conventional optical imaging methodology and has been routinely used in clinics for retinal structure change evaluation in addition to visual field tests. Devices such as a fundus camera, a scanning laser ophthalmoscope (SLO) or an indirect ophthalmoscope are routinely used for such testing. The retinal image provides valuable information that clinicians can utilize to diagnosis eye diseases. However, only qualitative interpretation of eye structure changes from the retinal photographs can be observed by highly experienced clinicians.
Accordingly, OCT has been used for non-invasive human eye retinal imaging. The cross sectional retinal image provided by an OCT system may allow a clinician to quantitatively evaluate the retinal nerve layer and retinal thickness. Thus, the OCT system may provide valuable clinical information that can be used for early diagnosis of eye diseases, such as Age-Related Macular Degeneration, Diabetic Retinopathy and Glaucoma.
OCT has been adopted as a standard of care for structural imaging of the eye for retinal and anterior structures. Video fundus photography and scanning laser ophthalmoscopy remain important modalities for capturing high resolution, high contrast en face photographs. Additionally, these modalities are useful for color photography and fluorescent imaging that provide complementary signatures of disease.
To date, OCT imaging systems have been largely bulky tabletop systems appropriate to clinical imaging of ambulatory patients. Handheld OCT produced by Bioptigen is the first compact system for ophthalmic imaging of pediatric, confined, or infirm patients that does not require the patient to sit a tabletop instrument as discussed in commonly assigned United States Patent Publication No. 2009/0268020.
The details of OCT systems used for imaging the human eye are discussed in, for example, U.S. Pat. No. 7,140,730 to Jay Wei et al. entitled Optical Apparatus and Method for Comprehensive Eye Diagnosis, the disclosure of which is hereby incorporated herein by reference as if set forth in its entirety. OCT scanners used for imaging the human eye are discussed, for example, in U.S. Pat. No. 6,741,359 to Jay Wei et al. entitled Optical Coherence Tomography Optical Scanner, the disclosure of which is hereby incorporated herein by reference as if set forth in its entirety.
Further discussion of OCT and related systems, methods and computer program product can be found in commonly assigned U.S. Pat. No. 7,830,525 and United States Patent Publication Nos. 2007/0081166; 2010/0315592; 2010/0321636; 2009/0141237 and 2009/0268161, the disclosures of which are hereby incorporated herein by reference as if set forth in their entirety.